1. Field of the Invention
The present invention relates to sextants. More particularly, this invention pertains to a drum screw, having a measuring drum mounted on the extended drum-screw axis, for fine adjustment of the engagement of the drum screw into the limbus toothing on the sextant's limbus body.
2. Description of the Prior Art
In order to be able to ensure a high measuring accuracy, the drum screw of a sextant must engage into the limbus toothing in axial, radial and tangential directions with a contact pressure that is defined as precisely as possible. An angled leaf spring, supported on the measuring-drum bearing and pressing against the face end of the drum-screw axis was previously employed to achieve the necessary axial component. In addition, the contact pressure or friction of the drum screw against its bearing bush must, however, also be precisely defined.